Field of the Invention
The present invention relates generally to electrocardiogram systems and, in one more particular embodiment, to a specialized method and/or system for digital to analog conversion (DAC) and reconstruction of multichannel electrocardiograms (ECGs), including 12-lead ECGs, compatible with multiple ECG manufacturers.
Background
Most modern electrocardiogram (ECG) machines use built-in analog to digital converters (ADCs) to digitize patients' analog cardiac electrical signals for more efficient analysis, display, storage, printing, and sharing of data. While this common and intuitive method has heretofore been sufficient for most clinical uses, this process typically “locks in” the practicing clinician to the often opaque and sometimes proprietary digital format(s) of the specific ECG machine(s) being employed. In contradistinction, and particularly for patients with difficult-to-interpret 12-lead ECGs wherein the automated diagnosis from the “house machine” may be in question (no automated algorithm being error free), many clinicians might welcome the opportunity to occasionally obtain one or more additional opinions from other manufacturers' automated interpretive algorithms. Different algorithms for example are sometimes known to have widely varying diagnostic accuracies for common electrocardiographic conditions.
As noted above, this can be problematic because each manufacturer uses competing proprietary programs to analyze the ECG data, restricting physicians and/or technicians to a particular automatic diagnostic algorithm. These diagnostic algorithms have variances that cause each of them to be better suited in diagnosing certain diseases and/or defects better than others.
Furthermore, most ECG machines are only designed to receive analog data, not digital data. Therefore, should a second automated opinion be necessary or advised, a patient must normally be subjected to a second ECG test, because the second ECG machine cannot readily receive the digital information generated in the first ECG machine to generate a second analysis. Even though it would be highly desirable to analyze data utilizing the diagnostic programs of different ECG machine manufacturers, there is presently no ready solution for ECG data generated on Manufacturer X's machine to subsequently be analyzed by Manufacturers Y's machine for diagnosis and second opinions.
The following background prior art patents disclose various types of ECG apparatuses, methods and/or systems, but do not address the problems discussed hereinbefore:
U.S. Pat. No. 7,197,357, issued Mar. 27, 2007 to Istvan et al., discloses a cardiac monitoring system and, more particularly, a wireless electrocardiograph (ECG) system. The base station converts the digital signals back to analog electrical signals that can be read by an ECG monitor. However, this art is directed at removing the plethora of cables associated with ECG machines and not solving the problem of compatibility issues between competing ECG manufacturers.
U.S. Pat. No. 6,611,705, issued Aug. 26, 2003 to Hopman et al., discloses a method and system for wireless ECG monitoring. An electrode connector, transmitter and receiver operate with existing electrodes and ECG monitors. The electrode connector includes connectors for attaching to disposable or reusable single electrodes. The transmitter transmits the signals from the electrodes to the receiver. The receiver passes the electrode signals to the ECG monitor for processing. ECG monitors used with an electrical conductor, for example wire connections to electrodes, are connected with the receiver. A Legacy ECG monitor is available to connect with the receiver using the ECG monitor's lead-wires. The ECG monitor operates as if directly connected to the electrodes without wires running from the ECG monitor to the patient.
U.S. Pat. No. 3,810,102, issued May 7, 1974 to Parks III, et al., discloses a method and system for transmitting biomedical data to a remote station for subsequent processing. Analog electrical biomedical signals are sampled and digitized at a relatively low data rate and transmitted over a communications link of limited bandwidth to a remote station where the analog electrical biomedical signals are reconstructed from the digital data and are sampled and digitized at a substantially higher data rate for subsequent interpretation by a diagnostic computer. Alternatively, the received digital data are directly converted to a substantially higher digital data rate by means of a numerical algorithm, a form of digital interpolation.
U.S. Pat. No. 8,082,027, issued Dec. 20, 2011, to Young, et al., discloses a system and method of the present application comprising ECG acquisition device having a USB connector for connecting the device to a host device and a patient connector for connecting the device to a patient with ECG leads. The ECG acquisition device of the present system further includes a processor and storage medium, a power management and brokering module, a USB communications control module, an ECG acquisition circuit, and a patient isolation module. The ECG acquisition device auto-loads and runs ECG monitoring software onto the host device.
U.S. Pat. No. 7,783,339, issued Aug. 24, 2010, to Lee, et al., discloses a method and system for real-time digital filtering for electrophysiological and hemodynamic amplifiers. The invention replaces the analog circuits currently used for signal filtering and conditioning in such systems with digital filters that may be implemented in a software application. The method and system includes digitizing the analog signal collected from the patient prior to performing the signal filtering and conditioning. The method and system also includes removing stimulus artifacts, as well as performing sample rate conversion and scaling on the digital signal. The processed digital signals may be used, displayed, saved and converted to analog signal through digital-to-analog conversion.
U.S. Pat. No. 7,184,921, issued Feb. 27, 2007, to Kohls, discloses a technique for encoding physiological data, such as a digital ECG, as a set of high-resolution symbols. The set of high-resolution symbols may be printed on a printout of the physiological data or other suitable medium. The set of high-resolution symbols may be scanned, or otherwise acquired, and decoded to reconstruct all or a portion of the original set of physiological data.
U.S. Pat. No. 6,735,464, issued May 11, 2004, to Onoda, et al., discloses an electrocardiograph system having an electrocardiograph transmitting cardiograms produced to outside equipment, and a communication device wirelessly communicating with the electrocardiograph. The communication device accepts a subject's posture selected from multiple posture options, and transmits a specific instruction signal to the electrocardiograph upon receiving the selection. The electrocardiograph stores a cardiogram produced when the instruction signal is received from the communication device as a reference cardiogram corresponding to the selected posture discriminating it from other cardiograms.
U.S. Patent Application No. 20100017471, issued Jan. 21, 2010, to Brown, et al., discloses systems and methods for providing improved medical care. A system includes a defibrillator, a gateway device, a routing device, and a wireless modem. The system may further include hardware and/or software components located at a remote facility for receiving data and one or more server devices for decoding data from the remote facility. A method includes acquiring medical data at a first location, converting the medical data from an analog signal to a digital signal, transmitting the digital signal from the first location to a second location over the internet via a cellular network, receiving the digital signal at the second location, and converting the digital signal back to an analog signal for processing. The first location may be an EMS vehicle, and the second location may be a remote facility, such as a dispatch center or local hospital.
There exists a need for a specialized method and system for digital to analog conversion (DAC) and reconstruction of multichannel electrocardiograms (ECGs) which addresses the problems associated with the prior art described hereinbefore. The present invention has direct commercial, military, and/or medical applications. Furthermore, the present invention would be valuable not only for further review of ECG data and second opinions, but also for improving diagnostic algorithms amongst ECG manufacturers through collaboration. Consequently, those skilled in the art will appreciate the present invention that addresses the above and other problems.